Hi bigdog, sorry for the tardy reply - I have to setup my email preferences to receive alerts or something - I never saw the message.
So when I tried to get them to fit on my 2003 Suburuban 2500 - what I found was that the Sulastic shackle pivot point - sticks out rearward from the spring. The shackle hanger mount which is bolted to the frame has "lips" on it , probably to give it strength from bending away from the frame. The Sulastic pivot point was too wide - or the lip on the hanger mount is too wide (depends which way you look at it ) - and the pivot point hits the lip on the hanger.
I could take some pics and post when I get a chance. I'm still planning on installing the Sulastics on my truck - I just have to do a little work to make them fit. I'm going to cut away the lips on the hangers enough so the Sulastics will clear - and then weld on a reinforcement at the bottom of the hanger so they don't bend.
I might be missing something - but I've looked at these on two different trucks and I see the same problem on both.
The issue is not present on the Silverado/Sierra 2500/3500 trucks because the frame is different and the hangers on the frame have enough clearance. The 2500 SUV frame is it's own beast.